<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        li {
            list-style: none;
        }

        img {
            vertical-align: top;
        }

        .a {
            width: 175px;
            height: 250px;
            background-color: #eee;
            /* 子元素的margin-top错误的传递到了父元素的时候，需要在父元素加overflow:hidden */
            overflow: hidden;
        }

        .a h3 {
            width: 140px;
            height: 37px;
            background-color: #ff0;
            margin-left: 19px;
            margin-top: 20px;
            border-bottom: 1px solid #000;
            /* 内边距会把盒子撑大 */
            padding-left: 14px;
            margin-bottom: 15px;
        }

        .a ul {
            margin-left: 30px;
            line-height: 24px;

        }

        .a ul li {
            background: #eee url(../images/qqq_03.jpg) no-repeat 0 center;
            padding-left: 14px;
        }
    </style>
</head>

<body>
    <div class="a">
        <h3>技术研发</h3>
        <ul>
            <li>科技力量</li>
            <li>科技力量</li>
            <li>科技力量</li>
            <li>科技力量</li>
            <li>科技力量</li>
        </ul>
    </div>
</body>

</html>